21320202131 has 4 divisors (see below), whose sum is σ = 21320762472. Its totient is φ = 21319641792.

The previous prime is 21320202121. The next prime is 21320202139. The reversal of 21320202131 is 13120202312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21320202131 - 2⁶ = 21320202067 is a prime.

It is a super-2 number, since 2×21320202131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21320202139) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 218585 + ... + 300698.

It is an arithmetic number, because the mean of its divisors is an integer number (5330190618).

Almost surely, 2^21320202131 is an apocalyptic number.

21320202131 is a deficient number, since it is larger than the sum of its proper divisors (560341).

21320202131 is an equidigital number, since it uses as much as digits as its factorization.

21320202131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560340.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21320202131 its reverse (13120202312), we get a palindrome (34440404443).

The spelling of 21320202131 in words is "twenty-one billion, three hundred twenty million, two hundred two thousand, one hundred thirty-one".